Forming tube for glass fibers



July 15, 1969 MCCLEERY a. CUNNINGHAM ETAI- 3,

FORMING TUBE FOR GLASS FIBERS Filed March 18, 1966 MQCLEERY BCUNNI H andCHAzLEs K. bum/$312.

ATTORNEY INVENTORS:

iinited States Patent US. Cl. 242-11832 2 Claims ABSTRACT OF THEDISCLOSURE A non-rigid forming tube comprising a plurality of spirallywound inner plies of paper, and a resin impregnated outer ply, the outerply having a roughened outer surface for the winding of glass fibersthereon, the tube being of sufiicient flexibibility to be collapsed in alongitudinal direction.

This invention relates to glass fiber manufacturing and moreparticularly to a carrier or forming tube for use in the winding offreshly spun glass filaments or fibers.

In the spinning of glass fibers to be processed into textile materialsuch as yarn and the like, glass in a molten condition is drawn throughsmall openings or orifices in a plate commonly referred to as aspinneret into the form of continuous filaments which solidify uponcontact with the air. These continuously drawn filaments are wound ontoa tubular carrier in the form of a flexible cylindrical sleeve which isgenerally referred to as a forming tube. In a glass fiber spinningoperation, this forming tube is slipped onto a spindle or the like whichis rotated at very high speeds, frequently around 8,000 to 10,00 rpm.and up, and the glass filaments are drawn from the spinneret and woundon the tube at a relatively high linear speed generally 10,000 to 12,000feet per minute and more. These forming tubes are used not only for sucha winding operation but for subsequent winding and unwinding operationsas well.

Due to the high speed at which the forming tube is rotated and therugged conditions of use to which it is subjected, these tubes must meetrigid standards and preferably should be of a suitable design andmaterial so as not only to be inexpensive in initial cost but to becapable of repeated use. Furthermore, these forming tubes must beprovided with external surface characteristics specifically suitable forthe glass fiber winding and unwinding operations for which they areused. In general, it can be said that such tubes are required to have arelatively smooth peripheral surface to permit the glass fibers to bereadily unwound from the tube and at the same time this peripheralsurface should be sufficiently rough so that satisfactory winding of thefibers on the tube may be accomplished. In addition, these tubes shouldalso be of light weight to avoid deformation by centrifugal force whichat the speeds referred to above is of a substantial magnitude.Furthermore, these forming tubes should be highly resistant tocompression by the fibers wound tightly on the tube so that the tubemaintains its shape after removal from the spindle and the tubes shouldhave sufficient flexibility and elasticity to permit their ready removalfrom the wound package of glass fibers when the tube is to be reused.

Two commonly employed materials in use today for making such formingtubes are plain paper or paperboard and plastic such as polyethyleneboth of which have 0bjectionable features. Although a forming tubecomposed solely of ordinary paperboard generally performs satisfactorilythe first time it is used, its inherent lack of strength and lack offlexibility causes it to deteriorate 3,455,521 Patented July 15, 1969rapidly when reused. It is throught that the rapid deterioration of suchpaper forming tubes occurs primarily as a result of the breaking of thecellulosic fibers in the tube resulting from the bending and folding towhich such paper tubes are subjected. Therefore, forming tubes offibrous material such as paper or paperboard are generally discardedafter a few uses or even after a single use adding considerably to themanufacturing costs of such glass fibers even though the initial cost ofsuch paper tubes is low. Forming tubes of plastic have also been usedwith some success but the severe stresses to which plastic forming tubesare subjected frequently causes plastic tubes to disentegrate or explodeduring use primarily as a result of centrifugal force not only creatinga hazard but, as a result of the high initial cost of such plastictubes, adding considerably to manufacturing costs.

Accordingly, a primary object of this invention is to provide a new andnovel non-rigid forming tube for use in the winding of glass filamentsor fibers.

Another object of this invention is to provide a new and novel spirallywound non-rigid forming tube for winding glass fibers which is formedfrom paper so as to be low in initial cost but at the same time ischaracterized by high strength and flexibility so as to be capable ofprolonged use with minimum deterioration.

A further object of this invention is to provide a new and novel'spirally wound non-rigid forming tube for winding glass fibers whichmay be simply and easily formed on a readily available-conventionalwinding apparatus within a range of winding angles which promoteflexibility and which reduce paper fiber breakage to a minimum.

Still another object of this invention is to provide a new and novelspirally wound non-rigid forming tube for winding glass fibers which isof low cost, high strength and flexibility so as to permit repeated useand easy removal from 'a wound glass fiber package and which is providedwith a highly suitable outer surface for the winding and unwinding ofglass fibers.

Other objects and advantages of the invention will become apparent fromthe following description taken in'connection with the accompanyingdrawing.

In general, the objects of this invention and other related objects areaccomplished by spirally winding at least one strip of paper intotubular form to form an inner ply. A strip of paper impregnated with asuitable resin is spirally wound in overlying relationship with theinner ply to form an outer ply and the resin is permitted to cure. Thepaper strips forming the inner and outer plies have fibers lyinggenerally in the direction of the longitudinal axis of the plies and theplies are spirally wound at a winding angle within the range of 17-35degrees. When the resin has cured, the outer surface of the outer paperply is provided with a hard, irregularly roughened outer surface for thewinding and unwinding of glass fibers. The inner and outer paper pliesare of sufficient flexibility so that the resulting forming tube isflexible to permit the forming tube to be collapsed longitudinally forremoval of the tube from a package of glass fibers wound thereon.

The novel features which are believed to be characteristic of theinvention are set forth with particularity in the appended claims. Theinvention itself, however, both as to its organization and method ofoperation may be best understood by reference to the followingdescription taken in conjunction with the accompanying drawing in which:

FIGURE 1 is a diagrammatic illustration of tube winding apparatus forwinding the forming tube of the invention;

FIGURE 2 is a sectional View taken substantially along 3 line 22 ofFIGURE 1 in the direction of the arrows;

FIGURE 3 is an enlarged isometric view of the tube of the invention aswound on the apparatus of FIGURE 1;

FLIGU'RE 4 is an enlarged sectional view taken substantially along line4-4 of FIGURE 3 in the direction of the arrows; and

FIGURE 5 is a view similar to FIGURE 4 showing the forming tube of theinvention in a collapsed condition.

Referring now to the drawing and to FIGURE 1 in particular, there isshown diagrammatically a typical spiral tube winding apparatus by meansof which the winding of the forming tube of the inventoin is carriedout. As previously stated, the forming tube of the invention, which isshown in section and designated generally by the numeral 11 in FIGURES4, 5, is of the type which is particularly suitable for use in thewinding of freshly spun glass filaments or fibers drawn from thespinneret of a glass furnace. However, the tube 11 of the invention mayalso be employed in other glass fiber manufacturing operations involvingglass fiber winding and ke-off procedures.

As generally illustrative of the method of winding the forming tube 11of the invention, the conventional spiral tube winding apparatus ofFIGURE 1 is designated generally by the numeral 12. This spiral tubewinding apparatus 12 is shown carrying out a winding ope-ration by meansof which a continuous tube T advanced in the direction of the arrow I isproduced. The tube T is cut into suitable lengths to form the formingtube 11 of the invention as will be explained hereinafter.

tube3 1 is therefore provided with a spiral butt seam 23a and paper ply21 is provided with an internal butt seam 21a.

As the paper tube 31 advances along the mandrel 14 down from the belt16, a strip 32 of paper impregnated with a suitable resin is spirallywound in overlying relationship with the wound paper ply 23 of the woundpaper tube 31 to form a spirally wound outer ply. Strip 32 is also .ofpaper 'but is of a type of paper which is of greater porosity andflexibility as well as greater strength than the paper plies 21, 23. Forinstance, a type of paper commonly referred to as kraft paper ispreferably used for As is well known, the spiral tube winding apparatus12 comprises a frame 13, a stationary mandrel 14 supported on the frame,a flexible endless belt 16 extending around a pair of pulleys 17 atleast one of which is driven for rotating and advancing the tube T as itis formed and a cutoff device 18 for cutting the continuously wound tubeT into uniform sections of a selected length.

In the winding of the continuous tube T, at least one strip 21 of paperunwound from a supply roll 22 is first wound on the tube making mandrel14. Preferably, two such paper strips are employed and accordingly asecond paper strip 23 unwound from a supply roll 24 is wound inoverlying staggered relationship -with and at the same angle as thestrip 21 from the opposite side of the mandrel 12. The paper strips 21,23 which contain cellulosic fibers common to paper have the fibersextending lengthwise in the direction of the longitudinal axis of thepaper strips or what is generally referred to as the paper machinedirection.

As shown in FIGURE 1, the angle at which the paper strips 21, 23 arewound onto the mandrel 14 is preferably within the range of 17 todegrees relative to the longitudinal axis of the mandrel 14 and, in theillustrated'embodiment ,the strips 21, 23 are wound at a winding angleof lapproximately" 29 degrees. Thus, at. the relatively low windingangle of 29 degrees, the fibers in the strips 21, 23 approach a parallelrelationship with the axis of the tube T for a purpose to be explainedhereinafter.

In order to adhere the paper strips 21, 23 together in the spirallywound relationship, the paper strip 23 is advanced in contact with anapplicator roll 26 suitably supported for rotation in a receptacle 27containing a suitable adhesive in the well known manner. Thus, theapplicator roll 26, as it rotates, applies adhesive to the underside ofstrip 23. Contact between the strip 23 and the applicator roll 26 ismaintained by advancing the strip 23 under guide rollers 28, 29 alsosuitably supported for rotation on the receptacle 27.

I In this manner, the ,two paper strips 21, 23, spirally wound ,withadhesive therebetween, form a two ply tube 31 which is advanced underthe belt 16 in the direction of the arrow 1. The paper strips 21, 23 arepreferably each wound with the edges of adjacent convolutions in anabutting relationship. As shown in FIGURE 3, paper the outer ply 32. Thewinding angle of the kraft paper strip 32 is also within the range of17-35 degrees and, as shown, is preferably wound at an angle of 29degrees.

The strip 32' is unwound from a supply roll 33 and is impregnated with asuitably resinous material by advancing the strip 32 through areceptacle 34 containing an impregnating resin bath 36 as shown inFIGURE 2. Preferably, the resinous material 36 is an acrylic resin whichis provided in the form of an aqueous emulsion. The curing of thisresinous material 36 may therefore be accomplished by the evaporation ofthe water vehicle from the acrylic resin and water mixture. Guiderollers 37-40 are suitably positioned as shown in FIGURE 2 adjacent thereceptacle 34 so that the strip 32 is immersed in the resinous emulsionbath 36 and subsequently removed for winding on the paper tube 31.Preferably, the impregnated strip 32 is wound with the edges of adjacentconvolutions in overlapping relationship as shown best in FIGURE 3 whichform an outer spiral seam 32a.

As the continuously formed tube T moves in the direction of the arrow I,it enters the cutoff device 18 in which it is cut into uniform sectionswhich are removed for curing. Preferably these tube sections are formedapproximately eight feet in length. The curing of the sections severedfrom the tube T is then carried out so that the water vehicle in theresin-water mixture in the tube outer ply 32 will be evaporated and theresin with which the tube T is impregnated will set permanently. Usingan aqueous acrylic resin mixture for impregnation of the tube ply 32permits the curing to be accomplished under normal room temperaturesover a relatively short period of time. However, if it is desired toshorten the curing time by the application of heat, means such as anoven can be utilized.

After curing, the tube sections are then cut into a plurality of shortlengths, preferably lengths of approximately eight inches to provideforming tubes 11 of a length suitable for use in a glass fiber windingand unwinding operation.

As a result of the high degree of porosity of the paper ply 32, asubstantial amount of resin 36 is absorbed into the outer ply 3-2. Inaddition, the flexibility of the paper strip 32 permits the ply toadhere in a continuous bond to the underlying paper ply 23 of the papertube 31. When the resin in the kraft paper outer ply 32 is cured, itforms a winding surface which is not only hard and durable butirregularly roughened so as to be ideally suitable for the winding andunwinding of glass fibers in certain operations.

It can be seen that the forming tube 11 of the invention is not onlycharacterized by high strength and durability so as to be capable ofrepeated use with a minimum of deterioration but it may be easilyremoved from the package of glass fibers wound thereon by collapsing thetube 11. As a result of the positioning of the fibers in the paperstrips 21, 23 and 32 at an angle approaching the angle of the axis ofthe tube T using a low strip winding angleof 17 to 35 degrees, thecollapsing of the tube 11, which is accomplished by folding the tubelongitudinally as shown in FIGURE 5, does not produce a folding acrossthe fibers but rather a folding in the general direction of the fibersso as to avoid fiber breakage thereby promoting long life for the tube11.

Having thus described the invention, 'what is claimed is:

1. A non-rigid forming tube for glass fibers comprising, in combination,a plurality of spirally wound inner plies of paper 'wound in overlyingstaggered relationship with adhesive therebetween, a spirally woundouter ply of resin impregnated paper having a hard, irregularlyroughened outer surface for the winding of glass fibers, each of saidinner and outer paper plies having its fibers lying generally in thedirection of the longitudinal axis of said plies and having a thicknessand composition for permitting said forming tube to flex readily andcollapsed longitudinally for removal of the tube from a package of glassfibers wound thereon, said inner and outer plies being spirally wound ata winding angle of between about 17 to 35 degrees, and the paper of saidouter resin impregnated paper ply having a flexibility, porosity andstrength greater than said inner paper plies for absorption of saidresin and to provide a more durable winding surface on said tube.

2. A non-rigid forming tube in accordance with claim 1 wherein saidwinding angle is approximately 29 degrees.

References Cited UNITED STATES PATENTS 2,751,936 6/1956 Dunlap et al.242-11832 X 2,945,638 7/1960 Crawford et al. 242-11832 3,002,872 10/1961Dunlap et al. 242118.32 X 3,054,428 9/1962 Crawford 242118.32 X3,194,275 7/1965 Biggs et al. 138144 GEORGE F. MAUTZ, Primary ExaminerUS. Cl. X.R.

